RISC-V: PR28733, add missing extension info to 'unrecognized opcode' error

Currently we report errors as "unrecognized opcode `fence.i'" when the
opcode isn't part of the selected extensions.
This patch expands that error message to include the missing extension
information. For example, now the error message would be "unrecognized
opcode `fence.i', extension `zifencei' required".
If the opcode is not a part of any extension, the error message reverts
to "unrecognized opcode `<op statement>'".

Signed-off-by: Patrick O'Neill <patrick@rivosinc.com>

bfd/
	pr 28733
	* elfxx-riscv.c (riscv_multi_subset_supports_ext): New function,
	used to return the extension string for each INSN_CLASS_*.
	* elfxx-riscv.h: Added extern riscv_multi_subset_supports_ext.
gas/
	pr 28733
	* config/tc-riscv.c (struct riscv_ip_error): New structure,
	contains information about errors that occur within the riscv_ip.
	(riscv_ip): Use struct riscv_ip_error to report more detailed errors.
	* testsuite/gas/riscv/c-fld-fsd-fail.l: Updated.
	* testsuite/gas/riscv/march-imply-i2p1-01.: Likewise.

1 files changed, 94 insertions, 0 deletions

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index 27d06d2fa3..d74e7a584e 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -2402,3 +2402,97 @@ riscv_multi_subset_supports (riscv_parse_subset_t *rps,
       return false;
     }
 }
+
+/* Each instuction is belonged to an instruction class INSN_CLASS_*.
+   Call riscv_subset_supports_ext to determine the missing extension.  */
+
+const char *
+riscv_multi_subset_supports_ext (riscv_parse_subset_t *rps,
+				 enum riscv_insn_class insn_class)
+{
+  switch (insn_class)
+    {
+    case INSN_CLASS_I:
+      return "i";
+    case INSN_CLASS_ZICSR:
+      return "zicsr";
+    case INSN_CLASS_ZIFENCEI:
+      return "zifencei";
+    case INSN_CLASS_ZIHINTPAUSE:
+      return "zihintpause";
+    case INSN_CLASS_M:
+      return "m";
+    case INSN_CLASS_A:
+      return "a";
+    case INSN_CLASS_F:
+      return "f";
+    case INSN_CLASS_D:
+      return "d";
+    case INSN_CLASS_Q:
+      return "q";
+    case INSN_CLASS_C:
+      return "c";
+    case INSN_CLASS_F_AND_C:
+      if (!riscv_subset_supports (rps, "f")
+	  && !riscv_subset_supports (rps, "c"))
+	return "f' and `c";
+      else if (!riscv_subset_supports (rps, "f"))
+	return "f";
+      else
+	return "c";
+    case INSN_CLASS_D_AND_C:
+      if (!riscv_subset_supports (rps, "d")
+	  && !riscv_subset_supports (rps, "c"))
+	return "d' and `c";
+      else if (!riscv_subset_supports (rps, "d"))
+	return "d";
+      else
+	return "c";
+    case INSN_CLASS_F_OR_ZFINX:
+      return "f' or `zfinx";
+    case INSN_CLASS_D_OR_ZDINX:
+      return "d' or `zdinx";
+    case INSN_CLASS_Q_OR_ZQINX:
+      return "q' or `zqinx";
+    case INSN_CLASS_ZBA:
+      return "zba";
+    case INSN_CLASS_ZBB:
+      return "zbb";
+    case INSN_CLASS_ZBC:
+      return "zbc";
+    case INSN_CLASS_ZBS:
+      return "zbs";
+    case INSN_CLASS_ZBKB:
+      return "zbkb";
+    case INSN_CLASS_ZBKC:
+      return "zbkc";
+    case INSN_CLASS_ZBKX:
+      return "zbkx";
+    case INSN_CLASS_ZBB_OR_ZBKB:
+      return "zbb' or `zbkb";
+    case INSN_CLASS_ZBC_OR_ZBKC:
+      return "zbc' or `zbkc";
+    case INSN_CLASS_ZKND:
+      return "zknd";
+    case INSN_CLASS_ZKNE:
+      return "zkne";
+    case INSN_CLASS_ZKNH:
+      return "zknh";
+    case INSN_CLASS_ZKND_OR_ZKNE:
+      return "zknd' or `zkne";
+    case INSN_CLASS_ZKSED:
+      return "zksed";
+    case INSN_CLASS_ZKSH:
+      return "zksh";
+    case INSN_CLASS_V:
+      return "v' or `zve64x' or `zve32x";
+    case INSN_CLASS_ZVEF:
+      return "v' or `zve64d' or `zve64f' or `zve32f";
+    case INSN_CLASS_SVINVAL:
+      return "svinval";
+    default:
+      rps->error_handler
+        (_("internal: unreachable INSN_CLASS_*"));
+      return NULL;
+    }
+}